Methods of forming layers comprising epitaxial silicon

ABSTRACT

The invention includes methods of forming layers comprising epitaxial silicon. In one implementation, an opening is formed within a first material received over a monocrystalline material. Opposing sidewalls of the opening are lined with a second material, with monocrystalline material being exposed at a base of the second material-lined opening. A silicon-comprising layer is epitaxially grown from the exposed monocrystalline material within the second material-lined opening. At least a portion of the second material lining is in situ removed. Other aspects and implementations are contemplated.

TECHNICAL FIELD

This invention relates to methods of forming layers comprising epitaxialsilicon.

BACKGROUND OF THE INVENTION

Silicon is a common semiconductive material used in the fabrication ofintegrated circuits. Silicon can occur in crystalline and amorphousforms, and when crystalline can be monocrystalline or polycrystalline.In some instances, silicon is combined with germanium, essentiallyforming a silicon germanium alloy. Such materials can be doped withconductivity enhancing impurities (i.e., boron and/or phosphorus) tomodify the conducting characteristics of the silicon-comprisingmaterial.

Monocrystalline silicon can be provided in bulk substrate form orotherwise grown or deposited epitaxially from an exposed monocrystallinematerial. Epitaxy generally involves the growth or deposition of asingle or monocrystalline layer of material such that the epitaxiallayer has a crystal orientation which is common to that of the materialfrom which it is grown. One factor that determines the quality of theepitaxial silicon-comprising layer relates to the presence and quantityof crystallographic defects. Such are non-uniformities in the crystalstructure of the epitaxial layer. Many of these defects are caused bydefects appearing at the surface of the substrate which propagate intothe layer during growth. Examples include sidewall dislocations andstacking faults. Dislocations and stacking faults can be electricallyactive more so than the surrounding material within the epitaxial layerdue to the presence of dangling bonds. Such can lead to unnecessaryrecombination generation currents, lower breakdown voltages, highercurrent leakage and larger junction ideality factors.

One place where epitaxial silicon has been utilized is as one or more ofthe components in a field effect transistor. Transistor structurescomprise a channel region received between a pair of source/drainregions, and a gate configured to electrically connect the source/drainregions to one another through the channel region. The transistorconstructions utilized in semiconductor constructions are supported by asemiconductor substrate. The semiconductor substrate will have a primarysurface which can be considered to define a horizontal direction.Transistor devices can be divided into two broad categories based uponthe orientations of the channel regions relative to the primary surfaceof the semiconductor substrate. Specifically, transistor structureswhich have channel regions that are primarily parallel to the primarysurface of the substrate are referred to as planar or horizontaltransistor structures, and those having channel regions which aregenerally perpendicular to the primary surface of the substrate arereferred to as vertical transistor structures. Since current flowbetween the source and drain regions of a transistor device occursthrough the channel region, planar transistor devices can bedistinguished from vertical transistor devices based upon the directionof current flow as well as on the general orientation of the channelregion. Specifically, vertical transistor devices are devices in whichthe current flow between the source and drain regions of the devices isprimarily substantially orthogonal to a primary surface of asemiconductor substrate, and planar or horizontal transistor devices aredevices in which the current flow between source and drain regions isprimarily parallel to the primary surface of the semiconductorsubstrate.

Epitaxial silicon-comprising materials have been proposed for use inchannel regions of vertical transistors. Further, one or both of thesource/drain areas of a vertical transistor might also compriseepitaxially grown silicon or an epitaxially grown silicon germaniumalloy. Requirements for epitaxial materials within a vertically orientedchannel region are typically more stringent than for the use of suchmaterial in source/drain regions of horizontally oriented field effecttransistors. Further, fabrication of vertical field effect transistorstypically utilizes masks of oxide, nitride or other materials forself-aligned patterning of the epitaxial silicon-comprising materialduring its formation. The interface of the epi with these materials canbe a defect source. Further, the selective epitaxial growth of siliconfor vertical transistors typically utilizes lower depositiontemperatures as compared to blanket epitaxial silicon depositions.Unfortunately, the use of lower temperatures reduces surface mobilityand can also result in increased defects over that of higher temperatureprocessing. Also and regardless, thermal stress can be generated duringcool-down of the substrate from the temperature at which the epitaxialsilicon-comprising material was grown. This can result incrystallographic defects being generated after growth.

Further, where the epitaxial silicon-comprising material includesgermanium, such has an increased tendency for defect formation on thesurface during deposition due to mismatched lattice constants of siliconand germanium. These defects propagate and either terminate with otherdefects or at the surface. Regardless, after deposition,crystallographic defects are extremely difficult to remove or healwithin the bulk epitaxially grown material or at interfaces of suchmaterial with other materials.

While the invention was motivated in addressing the above identifiedissues, it is in no way so limited. The invention is only limited by theaccompanying claims as literally worded, without interpretative or otherlimiting reference to the specification, and in accordance with thedoctrine of equivalents.

SUMMARY

The invention includes methods of forming layers comprising epitaxialsilicon. In one implementation, an opening is formed within a firstmaterial received over a monocrystalline material. Opposing sidewalls ofthe opening are lined with a second material, with monocrystallinematerial being exposed at a base of the second material-lined opening. Asilicon-comprising layer is epitaxially grown from the exposedmonocrystalline material within the second material-lined opening. Atleast a portion of the second material lining is in situ removed.

In one implementation, a method of forming a layer comprising epitaxialsilicon includes providing an opening within a first material receivedover a monocrystalline material. Opposing sidewalls of the opening arelined with a second material, with monocrystalline material beingexposed at a base of the second material-lined opening. Asilicon-comprising layer is epitaxially grown from the exposedmonocrystalline material within the second material-lined opening at atemperature greater than 200° C. After the growing, at least a portionof the second material lining is removed prior to cooling theepitaxially grown silicon-comprising material to a temperature below200° C.

In one implementation, a method of forming a layer comprising epitaxialsilicon includes providing an opening within a first material receivedover a monocrystalline material. The opening comprises opposingsidewalls. Opposing walls are formed within the opening and which arelaterally displaced inwardly of the opposing sidewalls. A space isreceived between the opposing walls and the opposing sidewalls. Asilicon-comprising layer is epitaxially grown between the opposing wallsfrom monocrystalline material exposed at a base of the opening.

Other aspects and implementations are contemplated.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a diagrammatic sectional view of a semiconductor substrate inprocess in accordance with an aspect of the invention.

FIG. 2 is a diagrammatic top plan view of the FIG. 1 substrate, withFIG. 1 being a cut taken through line 1-1 in FIG. 2.

FIG. 3 is a view of the FIG. 1 substrate at a processing step subsequentto that shown by FIG. 1.

FIG. 4 is a view of the FIG. 3 substrate at a processing step subsequentto that shown by FIG. 3.

FIG. 5 is a view of the FIG. 4 substrate at a processing step subsequentto that shown by FIG. 4.

FIG. 6 is a view of the FIG. 5 substrate at a processing step subsequentto that shown by FIG. 5.

FIG. 7 is a diagrammatic sectional view of a semiconductor substrate inprocess in accordance with an aspect of the invention.

FIG. 8 is a diagrammatic sectional view of a semiconductor substrate inprocess in accordance with an aspect of the invention.

FIG. 9 is a diagrammatic sectional view of a semiconductor substrate inprocess in accordance with an aspect of the invention.

FIG. 10 is a diagrammatic sectional view of a semiconductor substrate inprocess in accordance with an aspect of the invention.

FIG. 11 is a view of the FIG. 10 substrate at a processing stepsubsequent to that shown by FIG. 10.

FIG. 12 is a diagrammatic sectional view of a semiconductor substrate inprocess in accordance with an aspect of the invention.

FIG. 13 is a view of the FIG. 12 substrate at a processing stepsubsequent to that shown by FIG. 12.

FIG. 14 is a view of the FIG. 13 substrate at a processing stepsubsequent to that shown by FIG. 13.

FIG. 15 is a view of the FIG. 14 substrate at a processing stepsubsequent to that shown by FIG. 14.

FIG. 16 is a view of the FIG. 15 substrate at a processing stepsubsequent to that shown by FIG. 15.

FIG. 17 is a view of the FIG. 16 substrate at a processing stepsubsequent to that shown by FIG. 16.

FIG. 18 is a view of the FIG. 17 substrate at a processing stepsubsequent to that shown by FIG. 17.

FIG. 19 is a diagrammatic sectional view of a semiconductor substrate inprocess in accordance with an aspect of the invention.

FIG. 20 is a view of the FIG. 19 substrate at a processing stepsubsequent to that shown by FIG. 19.

FIG. 21 is a diagrammatic sectional view of a semiconductor substrate inprocess in accordance with an aspect of the invention.

FIG. 22 is a view of the FIG. 21 substrate at a processing stepsubsequent to that shown by FIG. 21.

FIG. 23 is a view of the FIG. 22 substrate at a processing stepsubsequent to that shown by FIG. 22.

FIG. 24 is a view of the FIG. 23 substrate at a processing stepsubsequent to that shown by FIG. 23.

FIG. 25 is a view of the FIG. 24 substrate at a processing stepsubsequent to that shown by FIG. 24.

FIG. 26 is a diagrammatic sectional view of a semiconductor substrate inprocess in accordance with an aspect of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

Exemplary first embodiment methods of forming layers comprisingepitaxial silicon are initially described with reference to FIGS. 1-11.Referring to FIG. 1, a substrate, preferably a semiconductor substrate,is indicated generally with reference numeral 10. In the context of thisdocument, the term “semiconductor substrate” or “semiconductivesubstrate” is defined to mean any construction comprising semiconductivematerial, including, but not limited to, bulk semiconductive materialssuch as a semiconductive wafer (either alone or in assemblies comprisingother materials thereon), and semiconductive material layers (eitheralone or in assemblies comprising other materials). The term “substrate”refers to any supporting structure, including, but not limited to, thesemiconductive substrates described above. Substrate 10 comprises amonocrystalline material 12, for example and by way of example only,lightly doped monocrystalline silicon or a monocrystalline silicongermanium alloy. Such might be provided by any existing or yet-to-bedeveloped methods, for example as a bulk monocrystalline substrate, asemiconductor-on-insulator substrate, epitaxially grown, etc. A firstmaterial 14 has been formed over monocrystalline material 12, and in thedepicted exemplary embodiment on such material. In the context of thisdocument, “on” means in at least some direct physical contact therewith.First material 14 might comprise any insulative, semiconductive and/orconductive material (including conductively doped semiconductivematerial). Further, some or all of such material might be sacrificial,and some or all of such material might remain over the substrate in afinished integrated circuitry construction.

An opening 16 has been provided within first material 14. An exemplarymethod for forming the same comprises photolithographic patterning andetch, although any existing or yet-to-be developed methods are alsocontemplated. For example and by way of example only, opening 16 mightbe provided by laser ablation, masked or maskless formation of material14 over substrate 12, etc. In the embodiment exemplified by FIG. 1,opening 16 is formed within first material 14 to extend tomonocrystalline material 12. For purposes of the continuing discussion,opening 16 can be considered as having opposing sidewalls 17 and 18. Inone preferred implementation, the opening is formed to be in the shapeof a line trench formed within first material 14 (FIG. 2). Of course,opening 16 might be of any other shape including (by way or exampleonly) circular, elliptical, oval, etc. Further, opening 16 might notextend all the way to monocrystalline material 12, as will be apparentin the continuing discussion.

Exemplary insulative materials for first material 14 include Si₃N₄,SiO₂, and silicon oxynitride (SiO_(x)N_(y)). An exemplary conductivematerial for first material 14 includes doped carbon.

Referring to FIG. 3, a second material 20 has been deposited over firstmaterial 14 and to within opening 16 laterally over sidewalls 17 and 18.Second material 20 might be insulative or conductive, with all or someof such being removed in the inventive described fabrication methods,and as well may or may not constitute a portion of the finishedintegrated circuitry construction. Exemplary preferred insulativematerials include SiO₂, SiO_(x)N_(y), Si₃N₄, Al₂O₃ and HfO₂. Anexemplary conductive material includes doped carbon.

Referring to FIG. 4, second material 20 has been anisotropically etchedeffective to expose monocrystalline material 12 within opening 16. Suchdescribes but one preferred exemplary method of lining opposingsidewalls 17 and 18 of opening 16 with a second material 20, andexposing monocrystalline material 12 at a base 21 of secondmaterial-lined opening 16.

Referring to FIG. 5, a silicon-comprising layer 22 has been epitaxiallygrown from exposed monocrystalline material 12 within secondmaterial-lined opening 16. The epitaxial growth of silicon-comprisinglayer 22 might occur by any existing or yet-to-be developed methods. Anexemplary preferred technique includes a temperature range of from 300°C. to 1,000° C., and a pressure range of from 10 mTorr to 100 Torr.Exemplary preferred gases for the deposition of epitaxial siliconinclude dichlorosilane at 0.2 liters/minute, H₂ at 20 liters/minute, andHCl at 0.15 liter/minute in a single wafer processor having a chambervolume of from eight to twelve liters. If, by way of example only, thesilicon-comprising layer is to comprise a silicon germanium alloy, GeH₄is an exemplary preferred gas flowed proportionally relative to thevolume flow of dichlorosilane to achieve the desired concentration ofgermanium. In one exemplary implementation, the epitaxial growing occursat a temperature of greater than 200° C., more preferably at atemperature of at least 600° C., and even more preferably at atemperature of at least 800° C. Epitaxially grown silicon material 22might be provided to less than completely fill opening 16 (as shown),exactly fill opening 16, or overfill to extend above and outwardly ofopening 16 relative to materials 14 and 20. For purposes of thecontinuing discussion, second material lining 20 in FIG. 5 can beconsidered as having an elevational thickness 25.

Referring to FIG. 6, at least a portion of second material lining 20 hasbeen removed. In one preferred implementation, such removing occurs insitu. In the context of this document, “in situ” requires a statedaction to occur within the same chamber within which thesilicon-comprising layer was epitaxially grown.

In one preferred implementation, the removing of at least a portion ofsecond material lining 20 occurs prior to cooling the epitaxially grownsilicon-comprising material to a temperature below 200° C. The removingmight be conducted at a temperature the same as that of the epitaxialgrowing, greater than that of the epitaxial growing, or less than thatof the epitaxial growing. In specific preferred implementations, theremoving occurs at a temperature at or below the temperature of theepitaxial growing, preferably within 200° C. of that of the growing,more preferably within 100° C. that of the growing, and even morepreferably within 50° C. of that of the growing. In one preferredimplementation, the removing is at a temperature lower than that of thegrowing but not at lower than 600° C. With respect to such temperaturesat which the removing occurs, such are most preferably conducted insitu, although such is not required.

In one implementation, the removing occurs by etching, and for examplewith such etching preferably being selective relative to first material14. In the context of this document, a selective etch requires a removalrate of one material relative another at a ratio of at least 2:1.Exemplary preferred etching comprising wet etching. For example wherematerial 14 comprises silicon nitride and material 20 comprises silicondioxide, an exemplary wet etching chemistry for silicon dioxide which isselective to silicon and silicon nitride comprises a combination of HF,ammonium hydroxide and hydrogen peroxide. Regardless, the removing mightbe of only a portion of second material lining 20, or might be of allremaining of the second material lining (as shown in FIG. 6). By way ofexample only and not by way of limitation, a preferred reason forremoving at least some of the lining prior to cooling as described aboveis to minimize thermal stress against sidewalls of the epitaxially grownsilicon that would otherwise occur where material is received againstsuch sidewalls during cooling, thereby preferably advantageouslyminimizing dislocation faults that might otherwise occur uponappreciable cooling of the substrate if all of material 20 was present.Regardless, the removing by etching or otherwise might occur at atemperature at, below, or above a temperature at which the epitaxialgrowing occurs.

FIGS. 1-6 illustrate an exemplary embodiment wherein the removing is ofall remaining second material lining 20. By way of example only, FIG. 7depicts an alternate embodiment substrate fragment 10 a wherein only aportion of second material lining 20 has been removed, leaving portions20 a. Like numerals from the first embodiment are utilized whereappropriate, with differences being indicated with the suffix “a”.Further in accordance with the exemplary FIG. 7 embodiment, only aportion of elevational thickness 25 of second material lining 20 (FIG.5) has been removed in the embodiment of FIG. 7. However by way ofexample only, FIG. 8 depicts an exemplary alternate embodiment 10 bwherein all of an elevational thickness portion of elevational thickness25 has been removed, leaving second material lining 20 b. Like numeralsfrom the first embodiment are utilized where appropriate, withdifferences being indicated with the suffix “b”.

By way of example only, the FIGS. 1-8 embodiments depict most preferredimplementations wherein the stated removing occurs after the epitaxialgrowing has occurred. However, aspects of the invention also contemplateremoving at least a portion of the second material lining before thegrowing, for example as depicted with respect to a substrate fragment 10c in FIG. 9. Like numerals from the first embodiment are utilized whereappropriate, with differences being indicated with the suffix “c”. FIG.9 depicts the removal of a portion of second material 20, leaving secondmaterial masses 20 c prior to the growth of an epitaxialsilicon-comprising layer (not shown) having occurred. By way of exampleonly, processing might otherwise occur subsequent to FIG. 9 to produce aFIG. 7-like construction.

Further by way of example only, the exemplary FIGS. 1-9 embodimentsabove depict opening 16 formed within first material 14 as extending allthe way to monocrystalline material 12 prior to the lining of theopposing sidewalls of such opening. By way of example only, an exemplaryalternate embodiment 10 d is described with reference to FIGS. 10 and11. Like numerals from the first embodiment are utilized whereappropriate, with differences being indicated with the suffix “d”.Opening 16 d within first material 14 d does not extend tomonocrystalline material 12 prior to lining opposing sidewalls ofopening 16 d with second material 20 d.

Referring to FIG. 11, one or more anisotropic etching chemistries andtechniques have been utilized to extend opening 16 d to monocrystallinematerial 12. Processing could otherwise occur in accordance with thevarious other exemplary implementations described above, or otherwise.

Exemplary additional implementations are next described with referenceto FIGS. 12-20. Certain aspects of the above implementations might, ofcourse, be utilized or combined with those of the followingimplementations. Referring to FIG. 12, a semiconductor substrate inprocess is indicated generally with reference numeral 30. Such comprisesmaterials 12 and 14, preferably having the properties and attributes asdescribed in the FIGS. 1-6 embodiment. An opening 16 has been providedwithin first material 14, with such, for the purposes of the continuingdiscussion, comprising opposing sidewalls 17 and 18, and a base 48.Preferred manners of fabrication of opening 16 are as described above inconnection with the FIGS. 1-6 embodiment. Accordingly, opening 16preferably extends completely to monocrystalline silicon material 12,although such is not required.

Referring to FIG. 13, a second material 34 has been deposited over firstmaterial 14 within opening 16 and along opposing sidewalls 17 and 18,and to less than completely fill opening 16. Second material 34 isdifferent in composition from that of first material 14. In the depictedexemplary preferred embodiment, such has been deposited to a suitablethickness to be, and then is, subsequently anisotropically etched toexpose monocrystalline material 12 within opening 16. Such etchingmight, of course, etch all of second material 34 from over firstmaterial 14, although such is not depicted. Exemplary preferredmaterials for second material 34 are the same as those for firstmaterial 14, with different compositions being used for first material14 and second material 34.

Referring to FIG. 14, a third material 36 has been deposited over secondmaterial 34 within opening 16 to less than completely fill the remainingvolume of opening 16. Third material 36 is different in composition fromthat of second material 34. Further by way of example only, firstmaterial 14 and third material 34 might be of the same composition or ofdifferent compositions. Further by way of example only, FIG. 14 depictslayer 36 as having been deposited to a suitable thickness to be, andthen is, anisotropically etched to expose monocrystalline material 12within opening 16. Such etching might, of course, etch all of thirdmaterial 36 from over first material 14, although such is not depicted.

Referring to FIG. 15, the substrate has been suitably polished, forexample by chemical-mechanical polishing (CMP), effective to removethird material 36 and second material 34 from outwardly of firstmaterial 14.

Referring to FIG. 16, at least some of second material 34 has beenremoved from between first and third materials 14 and 36, respectively,within opening 16 effective to form respective spaces 40 between firstmaterial 14 and third material 36. In one implementation and by way ofexample only, the above-described FIGS. 12-16 embodiment provides butone exemplary manner of forming opposing walls 45 within opening 16which are laterally displaced inwardly of opposing sidewalls 17 and 18,with a space 40 being received between opposing walls 45 and opposingsidewalls 17 and 18. An exemplary preferred manner of forming theexemplary depicted walls 45 is by etching, for example wet etching ofsecond material 34. In the exemplary depicted FIG. 16 embodiment, theetching is of only some of second material 34 from between firstmaterial 14 and third material 36 within opening 16 such that spaces 40do not extend to monocrystalline material 12.

In one exemplary implementation, opposing walls 45 are comprised of acomposition the same as that of first material 14, and in one exemplarypreferred implementation, opposing walls 45 are of a compositionconsisting essentially the same as that of first material 14.Alternately by way of example only, opposing walls 45 might be comprisedof a composition different from that of first material 14. Further inone exemplary implementation, and as shown, opposing walls 45 extendfrom monocrystalline material 12. Further as shown and described, atleast some aspect of forming opposing walls 45 comprises etching in onepreferred implementation. In one preferred aspect, the etching comprisesetching a second material (i.e., material 34) different in compositionfrom that of first material 14 and different in composition from that ofopposing walls 45. Further in one implementation, the forming of theopposing walls comprises CMP, and in one exemplary preferred embodimentas described, comprises both etching and CMP. In one implementation, theCMP is of at least material from which the opposing walls are formed,and the etching is of at least a second material different incomposition from that of the first material and different in compositionfrom that of the opposing walls, and in one preferred implementation,with the CMP being of both the material from which the opposing wallsare formed and of the second material.

Referring to FIG. 17, a silicon-comprising layer 50 has been epitaxiallygrown between opposing walls 45 from monocrystalline material 12 exposedat base 48 of opening 16. In the depicted preferred embodiment wherespace 40 does not extend all the way to monocrystalline material 12, theepitaxial silicon growing does not also grow a silicon-comprising layerwithin spaces 40. Preferred manners of growing and compositions forepitaxial silicon-comprising 50 are the same as those described above inconnection with the earlier embodiments.

In one exemplary embodiment, at least some of opposing walls 45 areetched after the epitaxial growing, and in one embodiment all remainingof such walls are etched after the epitaxial growing, for example asdepicted in FIG. 18. FIG. 18 also depicts remaining second material 34having been etched from the substrate in one preferred implementation.

FIGS. 19 and 20 depict an alternate exemplary embodiment substratefragment 30 a. Like numerals from FIGS. 12-18 embodiment are utilizedwhere appropriate, with differences being indicated with the suffix “a”.Referring to FIG. 19, such differs from that of FIG. 16 in that all ofsecond material 34 (not shown in FIG. 19) has been removed from betweenfirst material 14 and third material 36. Accordingly, spaces 40 a extendall the way to monocrystalline material 12.

Referring to FIG. 20, silicon-comprising layer 50 a has been epitaxiallygrown within opening 16 from monocrystalline material exposed at base 48of opening 16 and from that exposed within spaces 40 a.

The above exemplary FIGS. 12-20 embodiments form opening 16 within firstmaterial 14 to extend to monocrystalline material 12 prior to depositingsecond material 34. By way of example only, an alternate exemplaryembodiment substrate fragment 30 b is described in connection with FIGS.21-25 wherein the opening formed within the first material does notextend to monocrystalline material 12 prior to depositing the secondmaterial. Like numerals from the FIGS. 12-20 embodiments are utilizedwhere appropriate, with differences being indicated with the suffix “b”or with different numerals. Referring to FIG. 21, opening 16 b withinmaterial 14 b has been initially formed to not extend to monocrystallinematerial 12. Second material 34 b has been deposited to within opening16 b.

Referring to FIG. 22, second material 34 b and material 14 b withinopening 16 b have been anisotropically etched effective to exposemonocrystalline material 12. Such etching might, of course, etch all ofsecond material 34 b from over first material 14 b, although such is notdepicted. For purposes of the continuing discussion, first material 14 bwithin opening 16 b can be considered as having respective shelves 75 offirst material 14 b over which second material 34 b is received withinopening 16 b.

Referring to FIG. 23, third material 36 b has been formed as shown oversecond material 34 b within opening 16 b. Material 36 b in one preferredimplementation has been deposited and anisotropically etched effectiveto expose monocrystalline material 12. Such etching might, of course,etch all of third material 36 b from over first material 14 b, althoughsuch is not depicted.

Referring to FIG. 24, third material 36 b and second material 34 b havebeen polished at least to an outer surface of first material 14 b.

Referring to FIG. 25, all remaining of second material 34 b has beenetched from between first material 14 b and third material 36 b to shelf75 of first material 16 b.

Attributes of the invention encompass methods of incorporating any ofthe above-described epitaxial layers into a component of a field effecttransistor. By way of example only, a preferred such component comprisesa channel region of a field effect transistor, and further preferablywhere the field effect transistor is vertically oriented. For exampleand by way of example only, FIG. 26 depicts a substrate fragment 130comprising a substrate 132 and associated vertical field effecttransistor 133. Substrate 132 preferably comprises a semiconductorsubstrate, and for example as depicted, transistor 133 comprises adiffusion region 134 or other region formed within semiconductivematerial (i.e., monocrystalline silicon, whether bulk, epitaxially grownor otherwise) and which comprises a source/drain region of transistor133. Substrate fragment 130 comprises a projecting layer 136, forexample including one or more of the epitaxial layers formed, and ofcompositions, as described above. A gate dielectric layer 138 isreceived over substrate 132 and epitaxial silicon-comprising projection136. An exemplary preferred material is one or a combination of silicondioxide and silicon nitride. A transistor gate 140 is received aboutprojection 136. Exemplary preferred materials include one or acombination of conductively doped polysilicon, elemental metals, alloysof elemental metals, and conductive metal compounds. Projection 136comprises a source/drain region 142 received elevationally outward ofgate 140, and a channel region 150 therebetween. Conductivity enhancingdoping within regions 134 and 142 would be higher than that of channelregion 150, with transistor gate 140 being switchable to control currentflow between source/drain regions 134 and 142 through channel region150. Of course, some or all of the source/drain regions of thetransistor might be fabricated to be encompassed by projection 136, withthe gate 140 being sized appropriately.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A method of forming a layer comprising epitaxial silicon, comprising:providing an opening within a first material received over amonocrystalline material, the first material comprising semiconductivematerial; lining opposing sidewalls of the opening with a secondmaterial, monocrystalline material being exposed at a base of the secondmaterial-lined opening; epitaxially growing a silicon-comprising layerfrom the exposed monocrystalline material within the secondmaterial-lined opening; and in situ removing at least a portion of thesecond material lining.
 2. The method of claim 1 wherein the removingoccurs after the growing.
 3. The method of claim 1 wherein the removingoccurs before the growing.
 4. The method of claim 1 wherein the removingcomprises etching, the etching being selective relative to the firstmaterial.
 5. The method of claim 1 wherein the opening formed within thefirst material extends to the monocrystalline material prior to saidlining of the opposing sidewalls.
 6. The method of claim 1 wherein theopening formed within the first material does not extend to themonocrystalline material prior to said lining of the opposing sidewalls.7. The method of claim 1 wherein the opening comprises a line trench inthe first material.
 8. The method of claim 1 wherein the second materialis insulative. 9-14. (canceled)
 15. The method of claim 1 wherein thesecond material is conductive.
 16. (canceled)
 17. The method of claim 1wherein lining of the opposing sidewalls comprises deposition of thesecond material over the first material and to within the opening,followed by anisotropic etching of the second material effective toexpose the monocrystalline material.
 18. The method of claim 1 whereinthe removing occurs at a temperature below a temperature at which thegrowing occurs.
 19. The method of claim 1 wherein the removing occurs ata temperature above a temperature at which the growing occurs.
 20. Themethod of claim 1 wherein the removing occurs at a temperature at whichthe growing occurs.
 21. The method of claim 1 wherein the removing is ofall remaining of the second material lining.
 22. The method of claim 1wherein the removing is of only a portion of the second material lining.23-105. (canceled)
 106. The method of claim 1 wherein the semiconductivematerial is conductively doped.